1. Technical Field
The present invention relates to an ultrasonic transducer, an ultrasonic probe, an ultrasonic apparatus, an ultrasonic transducer manufacturing method, a vibration device, and the like.
2. Related Art
An ultrasonic transducer including a base portion having an opening and a piezoelectric element, which is provided on a vibration film that closes the opening, is known. In such an ultrasonic transducer, it is possible to transmit ultrasonic waves by driving the piezoelectric element to vibrate the vibration film or to detect (receive) the vibration of the vibration film when ultrasonic waves are input to the vibration film using the piezoelectric element (for example, refer to JP-A-2010-164331).
The efficiency of transmission or reception of ultrasonic waves in such an ultrasonic transducer depends on the distortion in the film thickness direction of a region (vibration region) of the vibration film that closes the opening. In order to improve the efficiency of transmission or reception of ultrasonic waves, it is necessary to increase the distortion of the vibration region. In this case, the two-dimensional shape of the vibration region when the ultrasonic transducer is viewed from the film thickness direction may be set to have a low aspect ratio.
Incidentally, in an ultrasonic transducer such as that disclosed in JP-A-2010-164331, the frequency of ultrasonic waves to be transmitted or received is determined by the area of the vibration region. In particular, in transmission and reception of high-frequency ultrasonic waves, it is necessary to further reduce the area of the vibration region. On the other hand, as described above, in order to efficiently transmit and receive ultrasonic wave, it is necessary to set the vibration region to have a low aspect ratio. In the configuration disclosed in JP-A-2010-164331, in a case where the area of the vibration region is set to be small and a low aspect ratio is set, it is necessary to form the opening provided in the base portion very small. Accordingly, there is a problem that manufacturing is difficult and the mass productivity is lowered.